Games like Generic Space Game
Games like Generic Space Game include Rogue Legacy, Vampire Survivors, Skul: The Hero Slayer, Anomaly Agent, and Broforce. We matched them by the tags players give Generic Space Game on Steam (Side Scroller, Bullet Hell, 2D Platformer, Shooter, and Roguelike): closest matches first, and among equally close ones the better-known games.

Rogue Legacy
Shared: Roguelike · Platformer · 2D

Vampire Survivors
Shared: Bullet Hell · 2D · Roguelike

Skul: The Hero Slayer
Shared: Roguelike · 2D · Action

Anomaly Agent
Shared: Side Scroller · 2D Platformer · Platformer

Broforce
Shared: 2D · Platformer · Side Scroller

Super Meat Boy
Shared: 2D Platformer · Platformer · 2D

Enter the Gungeon
Shared: Bullet Hell · Roguelike · Indie

My Friend Pedro
Shared: Shooter · Side Scroller · Action

Neon Abyss
Shared: Roguelike · Platformer · Shooter

30XX
Shared: Side Scroller · 2D Platformer · Platformer

SANABI
Shared: 2D Platformer · Action · 2D

Gravity Circuit
Shared: Platformer · 2D Platformer · 2D

Touhou Hero of Ice Fairy
Shared: Bullet Hell · Side Scroller · Platformer

Mark of the Ninja
Shared: Platformer · Side Scroller · 2D

20XX
Shared: 2D Platformer · Platformer · Side Scroller

Terminator 2D: NO FATE
Shared: Side Scroller · 2D Platformer · Shooter

Thomas Was Alone
Shared: Side Scroller · 2D Platformer · Platformer

Touhou Luna Nights
Shared: Side Scroller · Bullet Hell · Platformer

Blade Assault
Shared: Roguelike · 2D Platformer · Platformer

Momodora: Reverie Under The Moonlight
Shared: Side Scroller · 2D Platformer · 2D

Rogue Legacy 2
Shared: Platformer · Action · Side Scroller

Rise & Shine
Shared: Side Scroller · Bullet Hell · 2D Platformer

Dungreed
Shared: Roguelike · 2D · Action

Cuphead
Shared: Platformer · 2D · Bullet Hell